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Road traffic pollution and industrial plant-induced pollution affect negatively the development of forest trees. How forest trees are affected by their growing environment is important for sustainable environment. The study aimed to investigate the physical, mechanical, chemical, and morphological properties of the Pinus nigra (black pine) tree which grows under different conditions. Tree samples were chosen from three different lands where were inside the forest (O), near the roadside (Y), and near the factory (F). It was studied whether there were any significant differences among the “O”, “Y” and “F” in terms of their wood properties such as physical, mechanical, chemical, and morphological. As a result, the “O” samples demonstrated more regular annual ring structure. On the other hand, it was observed that the “Y” samples had longer and wider tracheid cells. In addition, “Y” samples had better mechanical strength than “O” and “F”. Environmental pollution caused the presence of some different elements (chlorine and iron) in “Y” and “F”. As a result, it was determined that the trees growing near the roadside or near industrial plants have significant differences from forest trees which are far away from pollutions. It is possible to say that Pinus nigra (black pine) is resistant to environmental stress. For this reason, it can be recommended to use it as a barrier to reduce air pollution on the roadsides.

Tribe Lithospermeae (Boraginaceae) consists of ca. 26 genera and 470 species, in which Onosma constitutes approximately one third of the species (~150). Although the tribe is strongly supported as monophyletic, both generic and species boundaries remain ambiguous. Among them, not only the phylogenetic position of Eastern Asian Onosma species, but also the taxonomic limits of the genus remain unclear. Whether Eastern Asian Onosma is monophyletic, or the genus should be widened to include Maharanga, and maybe Cystostemon, are still open questions. For these reasons, I performed 16 phylogenetic analyses with different taxon coverages, alignments, gene regions and outgroups, with up to 746 taxa of tribe Lithospermeae and with five DNA regions, using data from GenBank. The results, with the widest taxon coverage to date, show that while genus Onosma is not monophyletic in any of the analyses, the phylogenetic relationships among Onosma s.s., Eastern Asian Onosma, Maharanga and Cystostemon differ among analyses. However, the approximately unbiased (AU) test showed that the topology (((Eastern Asian Onosma+Maharanga) Cystostemon) Onosma s.s.) is overwhelmingly supported. Therefore, the current study highlights the importance of taxon, gene and outgroup sampling in Onosma phylogenetics.

The aim of this paper was to investigate the effects of wood flour on the mechanical, morphological and thermal properties of poly (L-lactic acid) (PLA)-chitosan biopolymer composites produced by compression molding. The composites were characterized by a combination of mechanical properties, scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). The addition of chitosan to PLA matrix reduced the tensile strength from 57.1 MPa for pure PLA to 34.3 MPa for 5% chitosan and 11.5 MPa for 10% chitosan, and the flexure strength from 72.3 MPa for pure PLLA to 30.4 MPa for 5% chitosan and 24.6 MPa for 10% chitosan. The change trend in the young’s modulus was found to be similar as compare with the tensile strength. However, the flexure modulus generally increased with the addition of the chitosan as comparison with pure PLA. The mechanical properties of the PLA-chitosan blends with wood flour were found to be lower than theirs of the pure PLA. According to SEM images, some holes and small voids at various diameters on the fractured section of the all composites were seen. Tonset, T10%, T50%, T85% of the pure PLA decreased with the addition of both chitosan and wood flour. Thermal stability of the PLA-chitosan blends was determined to be better than the PLA-chitosan composites with wood flour.

Furniture is the general name given for the portable equipment used in various human activities such as seating, working and relaxing. They can be a product of design and is considered a form of decorative art. They can widely be manufactured with different adhesives. Biodegradable and biobased adhesives which have no toxic compounds and non-dangerous elements have been selected since the furniture is generally benefited in interior locations. Meanwhile, polyvinyl acetate (PVAc) is a thermoplastic polymer which is widely used in the furniture industry. In this study, tension and bending strength of the furniture joints bonded with polyvinyl acetate adhesives filled with nano-TiO2 and nano-SiO2 were investigated. Three materials; oak (Quercus robur) wood, beech (Fagus orientalis) wood and plywood made with beech veneers were selected, and the joints were prepared by mortise and tenon joints. The results showed that the maximum value for the tension strength and bending strength were obtained to beech wood and oak wood in 2% addition of nano-SiO2 fillers. The minimum values for the tension and bending strength nano-SiO2 were found to plywood and 4% loading.

Thermal instability is the one of the most important disadvantages of wood since it begins to decompose at a low temperature (˃110 °C). Many scientists, past and present, have conducted studies aimed at improving the thermal stability of wood. The aim of this study was to impregnate wood with nano-sized boron nitride (NBN) to improve its thermal stability and to investigate the changes in the properties of Scots pine (Pinus sylvestrist), Ash (Fraxinus exelsior), and Iroco (Chlorophora excelsa) woods after the impregnation. The effects of the impregnation with NBN also were investigated on the heat-treated woods. The impregnation was conducted with using full-cell method in a chamber under a pressure of 0.6 MPa for 1 h. Densities at 0% and 12% moisture content (MC), mechanical properties, color changes, thermal stability, and scanning electron microscopy (SEM/EDAX) analysis were determined. The test results showed that the impregnation of wood with NBN increased generally the flexural strength and elasticity of modulus at bending, but the NBN impregnation decreased generally the compression strength except for ACI, ATWI, IC, and ICI. It was also determined that the changes in density and color were statistically different after the impregnation. According to the SEM/EDAX results, deposits of nano-sized boron nitride were found inside the cell wall and on the pits. But the deposits were also determined in inside structure of the wood with EDAX analysis. Thermal stability in T10% and T50% of wood was found to improve after the impregnation with NBN. TG/DTG and DTA values for some samples were found to fluctuate due to the heterogeneous dispersion of the NBN in the wood.

The coating of wood and wood panel surfaces basically serves for surface protection and its surface can be improved at various user areas. Different application methods are used for the coating of MDF surface. These are methods such as curtain coating, spraying, rolling, knife, etc. In this study, suitability of pigment coating method instead of the traditional surface coating methods used for coating MDF panels and the effects of fire retardants on surface properties of MDF coated by the best appropriate coating mixture was investigated. Calcite and clay were used as coating pigment and latex, urea formaldehyde, and melamine formaldehyde were used as adhesive. Coating/adhesive mixture obtained was applied to MDF panels with knives. Before the analysis, test samples were put to condition room and they were kept in there for 1 week. According to the results obtained, the best appropriate coating material was found as calcite. 22% concentrated melamine formaldehyde as adhesive and 0.25 mm as coating thickness was determined better than other combinations. Borax, boric acid and zinc borate as fire retardant were added to calcite /melamine formaldehyde with 22% mixture. So, the effects of fire retardant on surface characterization were determined. Surface properties of coated MDF panels tested were found lower than standard requirements except for abrasion resistance.

The heat treatment of wood is an environment-friendly method for wood preservation. The heat treatment process only uses steam and heat, and no chemicals or agents are applied to the material during the process. Tests have shown no harmful emissions are apparent when working with the material. This process improves wood’s resistance to decay and its dimensional stability. In this study, the density, compression strength and hardness of heat treated hornbeam (Carpinus betulus L.) wood were investigated. Wood specimens that had been conditioned at 65% relative humidity and 20ºC were subjected to heat treatment at 170, 190, and 210 °C for 4, 8, and 12 hrs. After heat treatment, compression strength and hardness were determined according to TS 2595 and TS 2479. The results showed that the decreases of compression strength and hardness were related to the extent of density loss. Both compression strength and hardness decreased with the increasing temperatures and durations of the heat treatment. While the maximum density loss observed was 16.12% at 210 ºC and 12 hour, at these heat-treatment conditions, the compression strength approximately decreased 30% and hardness values in tangential, radial, and longitudinal directions approximately decreased by 55%, 54%, and 38%, respectively. Hence, it was concluded that there might be a relationship between changes of these wood properties.

The heat treatment of wood is an environment-friendly method for wood preservation. The heat treatment process only uses steam and heat, and no chemicals or agents are applied to the material during the process. Tests have shown no harmful emissions are apparent when working with the ma-terial. This process improves wood’s resistance to decay and its dimensional stability. In this study, the density, compression strength and hardness of heat treated hornbeam (Carpinus betulus L.) wood were investigated. Wood specimens that had been conditioned at 65% relative humidity and 20 ºC were subjected to heat treatment at 170, 190, and 210 ºC for 4, 8, and 12 hrs. After heat treatment, compression strength and hardness were determined according to TS 2595 and TS 2479. The results showed that the decreases of compression strength and hardness were related to the extent of density loss. Both compression strength and hardness decreased with the increasing temperatures and durations of the heat treatment. While the maximum density loss observed was 16.12% at 210 ºC and 12 hour, at these heat-treatment conditions, the compression strength approximately decreased 30% and hardness values in tangential, radial, and longitudinal directions approximately decreased by 55%, 54%, and 38%, respectively. Hence, it was concluded that there might be a relationship between changes of these wood properties.

The coating of wood and wood panel surfaces basically serves for surface protection and its surface can be improved at various user areas. Different application methods are used for the coating of MDF surface. Th ese are methods such as curtain coating, spraying, rolling, knife, etc. In this study, suitability of pigment coating method instead of the traditional surface coating methods used for coating MDF panels and the effects of fi re retardants on surface properties of MDF coated by the best appropriate coating mixture was investigated. Calcite and clay were used as coating pigment and latex, urea formaldehyde, and melamine formaldehyde were used as adhesive. Coating/adhesive mixture obtained was applied to MDF panels with knives. Before the analysis, test samples were put to condition room and they were kept in there for 1 week. According to the results obtained, the best appropriate coating material was found as calcite. 22% concentrated melamine formaldehyde as adhesive and 0.25 mm as coating thickness was determined better than other combinations. Borax, boric acid and zinc borate as fi re retardant were added to calcite /melamine formaldehyde with 22% mixture. So, the effects of fi re retardant on surface characterization were determined. Surface properties of coated MDF panels tested were found lower than standard requirements except for abrasion resistance.